Multivoltage train telephone system



S. J. BARTHA MULTIVOLTAGE TRAIN TELEPHONE SYSTEM Nbv. 11, 1952 3Sheets-Sheet 1 Filed Dec. 50, 1948 3 2- VO LT. PO WE R SUPPLY 32V.PU INGINVENTOR. STEPHAN J. BARTHA ATTORNEY IFPatented Nov. 11, 1952MULTIVOLTAGE TRAIN TELEPHONE SYSTEM Stephan J. Bartha, Chicago, Ill.,assignor to Automatic Electric Laboratories, Inc., Chicago, 111., acorporation of Delaware Application December 30, 1948, Serial No. 68,349

9 Claims. 1

. The present invention relates to telephone sys terns in general, andmore particularly to telephone systems adapted for use in providingcommunication facilities between the cars of a railroad train or thelike.

Telephone systems suitable for train service comprise essentiallytelephone stations conveniently located in the cars of the train, a linehaving a plurality of conductors throughout the train forinterconnecting the telephone stations, and means for enablingpassengers or porters to signal and converse with dining car, club car,and other service car attendants, for the purpose of ordering food andrefreshments, and for requesting other services. Telephone systemspreviously designed for providing such services generally impose therestriction of requiring all cars included in the telephone system tohave the same power supply voltage for operating the telephone system,and additionally, many of such telephone systems further require thatthe cars be retained in a fixed sequential order on all runs.Restrictions of these natures place a severe handicap upon trainoperation and make-up, as cars are often equipped with power supplies ofdifferent voltages (for example, 32 volts, 64 volts, 110 volts), andthere are numerous occasions where a particular car, such as a club caror dining car, cannot occupy the same relative position in the trainmake-up on different runs.

It is, therefore, a primary object of the present invention to providean improved and efficient telephone system of the character described,wherein the cars comprising a train make-up can be equipped with powersupplies of different voltages for operating the telephone system, andwherein any car can occupy any desired position in the train assemblywith respect to the other cars.

Another object of the invention is to provide in a telephone system ofthe character described, new and novel means for completing calls from atelephone station in a car'equipped with a power supply of one voltageto a telephone station in a car equipped with a power supply ofdifferent voltage.

A further object of the invention is to provide in a telephone system ofthe character described, new and novel circuit means for establishingthe various telephone connections.

' A still further object of the invention is the provision in atelephone system of the character described, ofa new and novel methodfor quickly and conveniently changing the telephone number of a carwithout the unsoldering or rearranging of wired connections.

A feature of the invention resides in the novel arrangement whereby anindividual control conductor is included in the multiple lineinterconnecting the telephone stations of the cars for each differentpower supply voltage in the telephone system.

Another feature of the invention concerns the novel manner in which aplurality of pulsing relays are utilized in each car for controlling theoperation of the car telephone station selector,

Another feature of the invention relates to the improved pulsingarrangement wherein the power sup ly voltage of the car in which atelephone call is initiated is employed for operating one of the pulsingrelays in the calling car and corresponding pulsing relays in the othercars of the telephone system.

A still further feature of the invention is the provision that thetelephone station selector of each car is always operated from therelated car power supply, under control of a pulsing relay operated fromthe power supply of a calling car which may be of the same voltage or ofa different voltage. 7

Another feature of the invention concerns the new and novel manner inwhich any telephone station in any car can be readily restricted at anydesired time from connecting with certain other telephone stations inthe telephone system, without requiring unsoldering or re-arrangement ofwired connections.

Other objects and features of the invention will become apparent fromthe following specification together with the accompanying drawingswhich show a proposed embodiment by Way of example.

The invention is disclosed in three sheets of drawings comprisingFigures 1, 2, 3, 4, 5, 6 and 7 Figure 1 shows the complete controlapparatus and wiring for a telephone station located in a car equippedwith a 32-volt power supply.

Figure 2 shows the changes required in the arrangement and wiring of thecontrol apparatus shown in Figure 1 when the related car is equippedwith a 64-volt power supply.

Figure 3 shows the changes required in the arrangement and wiring of thecontrol apparatus shown in Figure 1 when the related car is equippedwith a -volt power supply.

Figure 4 shows the arrangement and wiring of a telephone which can belocated in any car and be permanently connected to the related 3 controlequipment, such as shown in Figures 1, 2 or 3, to serve as the regularcalling and receiving telephone station for that particular car. Figure5 shows the arrangement and wirin or" a plug-ending telephone equippedwith a signal and a dial which can be plugged into a multiple jack inany car to serve as an auxiliary telephone station.

Figure 6 shows the arrangement and wiring of a, plug-ending handsetwithout signal or dial Which can be plugged into a multiple jack in anycar to serve as an auxiliary answering telephone. Figure 7 shows atable, or chart, of 22 telephone station numbers and the relatedsettings of the number-changing switch such as I06 in Figure 1.

Referring to Figures 1 to '7, inclusive, a description of the equipmentand arrangement of the various units will now be given.

Telephone control apparatus for a car equipped with a 32-oolt powersupply As previously indicated, Figure 1 shows the complete controlapparatus and wiring for a telephone station located in a car equippedwith a 32-volt power supply. The apparatus includes the followingdescribed units:

A 26-point, three-level, rotary switch I00 of Well known design havingthree wipers IOI, I02 and H33 and associated levels of bank contacts,and a motor magnet I04 for causing the rotation of the wipers over thebank contacts. This rotary switch functions as a telephone stationselector for selecting the telephone station of the related car inresponse to the operation of a dial at a calling telephone station inanother car, and for completing the signal circuit of the calledtelephone station.

A 22-point, two-level, hand-operated rotary switch I06 (method of handcontrol not shown) having two wipers I0! and I08 and associated levelsof contacts for providing means to quickly and conveniently change thetelephone number of the relatedtelephone station without the necessityof unsoldering or re-arrangingwired connections.

A locking-type lever or push switch I 0,9 for restricting the relatedtelephone station from connecting with certain telephone stations in thetrain telephone system.

Three pulsing relays H9, I20 and I30 for controlling the stepping of thewipers of station selector I00. Relay IIO is arranged to operate on apower supply of 32 volts, relay I20 on a power supply of 64 volts,andrelay I30 on a power supply of 110 volts.

Control relays I35, hi0, I45 and I50 for performingcertain circuitfunctions which are explained in'a later section of the specification.

Various resistors and condensers associated with the pulsing and controlrelays for facilitating the operation of the relays in the various powersupply voltage combinations.

It should be understood at this time that while station selector I00andhand operated telephone number-changing switch I06 are disclosed ashaving certain bank contact capacities, these switches may equally aswell have larger or smaller bank contact capacities, according to needor preference.

It should be further understood that although pulsing relays H0, I20 andI30 have been specified as operative on power supplies of 32 volts, 64volts and 110 volts pressure respectively, the train telephone system isnot limited to these three voltage requirements or to three differentvolt- 4 ages, as any desired or required series of operat ing voltagesmay be employed.

Telephone control apparatus for a car equipped with a 64-21012? powersupply Figure 2 shows the changes required in the arrangement and wiringof the three pulsing relays of the control equipment when the relatedcar has a G l-volt power supply. In this instance pulsing relay 2I0(equivalent of pulsing relay H0) is arranged to operate on a powersupply of 64 volts, pulsing relay 220 (equivalent of pulsing relay I20)on a power supply of 32 volts, and pulsing relay 230 (equivalent ofpulsing relay I30) on a power supply of volts.

In order to simplify the drawings, it is considered unnecessary to showthe control equipment of Figure 2 in complete detail as reference can bemade to Figure l for the details not included in Figure 2. It should beunderstood, however, that if the control equipment of Figure 2 wascompletely illustrated, all of the apparatus and wiring shown in Figure1 would be included, except as modified by the specific changes nowshown in Figure 2, and that the wipers of the numberchanging switchcorresponding to switch I06 would be resting on contacts other than thecontacts #I of the respective bank levels in order that the telephonestation of Figure 2 would have a different telephone number.

Telephone control apparatus for a car equipped with a 11 O-volt powersupply Figure 3 shows the changes required in the arrangement and wiringof the three pulsing relays of the control equipment when the relatedcar has a 110-volt power supply. In this instance, pulsing relay 3"](equivalent of pulsing relay I I0) is arranged to operate on a powersupply of 110 volts, pulsing relay 320 (equivalent of pulsing relay I20)on a power supply of 32 volts, and pulsing relay 330 (equivalent ofpulsing relay I30) on a power supply of 64 volts.

Figure 3 also shows that since the operating voltage for motor magnet304 is 110 volts, resistor 3I6 has been inserted in the circuit of motormagnet 306.

Remarks similar to those in the last paragraph of the preceding sectionof this specification apply to this section concerning the controlequipment of Figure 3.

Fired station telephone with dial and signal The telephone equipment andwiring of the regular calling and receiving telephone station in eachcar included in the train telephone system is shown in Figure 4. Theapparatus of the telephone consists of a, handset 400 comprising atransmitter and a receiver, a cradle switch 40I located intermediate thecradle arms of the supporting members for handset 400 in the usualmanner, a dial-actuated impulsing device 402, and a signal device in theform of a buzzer 403.

The transmitter and the receiver of handset 400are preferably of thewell-known self-powered (sound-powered) type, so that it is unnecessaryto provide an auxiliary current source for voice frequency currenttransmission. A transmitter of the sound-powered type generally includesa diaphragm which is connected by means of alight connecting rod to anarmature balanced between the poles of a powerful permanent magnet. Whensound waves impinge upon the diaphragm, it vibrates in accordance withthese waves to transmit the vibrations to the armature which,

in turn, vibrates and sets up variations, in the magnetic lines offorce, both in number and direction. This causes an induced alternatingvoltage to be developed in th coil windings forming apart oftheimagnetic field which varies in amplitude and frequency in accordancewith the amplitude and intensity of the input sound waves.

Portable telephone with dial and signal Any car included in the traintelephone system can be fitted with a multiple outlet jack, or jacks,connected to the car telephone system-wiring in order that a portabletelephone may be plugged into a jack to serve as an auxiliary telephone.

station. Such a plug-ending portable telephone is illustrated in Figure5. V

The portable telephone consists of a handset 500 comprising atransmitter and a receiver of the sound-powered type, a cradle switch50!, a dial-actuated impulsing device 502, and a signal buzzer 503,interconnected and terminating in a six-conductor plug 504.

Portable handset without dial or signal operative by means of a pushbutton 602 pro truding through the handle of the handset, and afour-conductor cord terminating in a six-conductor plug 604.

Multiple train line The various regular calling and'receiving telephonestations are interconnected by means of a multiple train line consistingof six conductors extending throughout the train. These conductors ineach car are terminated in receptacles at the opposite ends of the car,and the adjacent receptacles of each two cars are coupled together bymeans of plug-ending flexible cable in wellknown manner.

Two of the conductors (Nil-I62) comprise the talking circuit, oneconductor each (I65. I64, I63) is respectively provided for the 32-volt,64-volt and l-volt pulsing circuits, and one conductor (I66) is used asa common conductor in the three diiferent voltage pulsing circuits.

Power connections for train telephone system It should be understood atthis time that while Figures 1, 2 and 3 each show a plurality ofnegative and positive power connections, such connections for eachfigure are preferably from the same power supply for that particularfigure. For example, Figure 1 shows two terminals H6 and I ll connectedto a 32-volt power supply and also a number of negative and positivepower connections to the various apparatus units, but al1 of thenegative and positive power connections for Figure 1 are from the sam32-volt power supply.

It should also be understood that in order to further'simplify thedrawings, spark quenching units comprising resistors and condensers havebeen omitted from the drawings. It should be further understood that anX contact shown in association with a relay armature in the drawings isa contact that makes or breaks before any other'contacts of theparticular relayare closed or opened, thus characterizing the relay as atwostep relay.

Having described the equipment and apparatus, a detail explanation ofthe operation of the train telephone system will now be given.

Number of telephone stations in train telephone system The embodimentshown in the drawings provides for a maximum number of 22 regularcalling and receiving telephone stations in the train telephone system.These calling and receiving telephone stations are usually located onein each car included in the train telephone system, although more thanone of such telephone stations can be located in any car so required. Inaddition, any car can be equipped with multiple jacks located at variouspoints in the car and connected tothe car telephone wiring so that aportable telephone or handset can be plugged into a multiple jack toserve as an auxiliary telephone.

It should be understood, however, that the invention is not limited to amaximum of 22 regular calling and receiving telephone stations, as agreater number of stations can be accommodated by providing larger bankcapacity switches in the control equipment located in each car includedin the train telephone system.

Figure 'l of the drawings provides a table, or chart, showing apreferred list of telephone numbers for the 22 regular calling andreceiving telephone stations. The column at the left lists the telephonenumbers, and the column at the right the associated settings of thehand-operated telephone number-changing switch (I06 in Figure 1) in eachcar.

The contacts of the two levels of hand-operated number-changing switchI06 are wired to the contacts of the center and lower bank levels ofstation selector H30 in the manner shown in Figure 1. Contacts of switchH36 are wired to the respective contacts #I of selector lllil, contacts#2 to the respective contacts #2, and so on until contacts #9 of switchH38 are wired to the respective contacts #9 of selector I08. Contacts#ll) of switch I26 are not wired to contacts IQ of selector m6 but tocontacts #I l of selector I89, leaving contacts #lil of selector [allvacant. Contacts #ll of switch WE are wired to contacts #l2 of selectorI and so on until contacts #l8 of switch its are wired to contacts #19of selector I68. Contacts #IQ of switch Hill are not wired to contacts#26 of selector I] but to contacts #2! of selector [68, leaving contacts#22 of selector lei! vacant. Contacts #25) of switch H06 are wired tocontacts #22 of selector I08, contacts #2! to contacts #23, and contacts#22 to contacts #2 l. 'Wipers iill and Hill of switch I06 arehand-operated to the respective contacts of desired telephone number, asindicated in thetable shown in Figure '7. Unwired contacts #iii and #29of the center and lower bank levels of selector Hill are home positionsfor the second and third digits of two-digit and three-digit telephonenumbers;

Changing telephone station numbers Should two or more cars have therelated tele phone number-changing switches (:65 in Figurel) cnthesamecontacts at the time these cars are coupled into the train telephonesystem, thereby establishing duplicate telephone station numbers in thetrain telephone system, it is a. simple matter to quickly and easilyhand-operate one-or more of the related telephone numberr 7 changingswitches so'that each car will have .a difierent telephone stationnumber. It will thus be seen that a novel means is providedforconveniently and rapidly changing thetelephone station number of acar wyithout unsoldering or re-arranging wired connections.

Combinations of cars in train teiephone system Since the drawingsdisclose a train telephone system in which one car (Figure 1) has a.32-volt power supply, a second car (Figure 2) a 64-volt power supply,and a. third car (Figure 3) a 110- volt power supply, and since thesecars are interconnected by means of a multiple train line which can beextended to other cars not shown on the drawings, it is apparent thatthe train telephone system can include any desired combination andnumber of cars having different voltage power supplies, up to themaximumpermissible number of regular calling and receiving telephonestations.

It is also apparent that, since the train line is arranged on a multiplebasis and there are no series circuits involved between the cars, anycar can occupy any desired location in the train telephone system withrespect to other cars regardless of the voltage of its power supply.

Outgoing call from a car equipped with a 32-volt power supply Assumingnow that a person in a car equipped with a 32-volt power supply (Figurel) initiates a call for a car equipped with a 1l0-volt power supply(Figure 3), then the detail circuit operation is as follows:

The handset 400 (Figure 4) is lifted from its cradle thereby causingcradle switch ,40I to assume the contact position shown in Figure .4. Atarmature spring 405 and closed contact, cradle switch 443i extendspositive 32-volt potential to armature I34 of relay I35 (Figure 1) byWay of terminal II1, conductor 406, armature spring 405 and closedcontact, and conductor 408. Assuming further at this point in theoperation that the multiple train line between the cars in the telephonesystem is unoccupied (idle), then relay I35 is in the normal unoperatedposition and the positive 32-volt potential is extended to the windingofline relay I50 through the resting contact associated with armature I34,causing line relay I50 to operate after a short interval.

At armatures I54, I55 and I5I, respectively, relay I50 disconnects thewindings of pulsing relays I I0, I and I from the 32-volt, 64-volt andl10-volt pulsing conductors of the multiple train line. At armature I52relay I50 extends negative 32-volt potential to the common train lineconductor I66 as part of the pulsing circuit to the other cars in thetrain telephone system. At armatures I52 and I54, relay I50 completesthe circuit of pulsing relay I.I0 from positive 32-volt potential onterminal II1, conductor 406, pulsing springs of dial 402, armaturespring 404 and closed contact, conductor 401, armature I54 and workingcontact, resistor II4, winding of relay IIO, armature I52 to negative32-volt potential on terminal H6, causing relay IIO to operate.

At armature I I I and working contact, relay I I0 completes a circuit torelay I from positive 32- volt potential by way of station selectorofi-normal armature spring I33 and resting contact to the winding ofrelay I 35 and negative 32-volt potential, causing relay I35 to operate.At armature II2, relay IIO completes a multiple 32-volt pulsing circuitto pulsing relay 220 (Figure 2) in the carhaving a 64-volt power supplyand to pulsing relay 320 (Figure 3) in the car having a 1-10-volt-powersupply, causing pulsing relays 220 and 230 to operate. The multiple32-volt pulsing circuit may 'be traced from positive 32-volt potentialon terminal II1 (Figure 1), resistor II3, armature I I2, armature I53,32-volt pulsing conductor I65 of the train lineto Figures 2 and 3, fromconductor I65 in Figure 2 armature 255, resistor 222, winding of pulsingrelay 2-20 to negative 3 2'-volt potential on common conductor I66 ofthe train line, and from conductor I65 in Figure 3, armature 355,resistor 3'22, winding of pulsing relay 320 to negative 32 -Voltpotential on common conductor I66 of the train line.

At armature I31, relay I35 completes a multiple circuit to its windingindependent of off-normal armature spring I33; at armature I34 andworking contact, completes a locking circuit to relay I50 by way ofarmature I51; and'at armature I33, completes circuits to relay I40 anddial tone relay I45. The circuit to relay I40 may be traced frompositive 32-vo1t potential on wiper IOI of station selector I00, 26thcontact of bank associated with wiper II'II, armature I38, upper windingof relay I40 to negative 3 2-volt potential. Relay I40 operates over thecircuit just traced, and connects condenser I23 to conductor 4 leadingto handset 400 by way oi armature MI and working contact and armatureI49. The circuit to dial tone relay I45 may be traced from positive32-volt potential on wiper I M, 26th contact of bank associated withwiper I0-I, armature I38, conductor II8, armature I58, upper winding ofrelay I45 to negative 32-volt potential.

Dial tone relay I45, in operating, closes its X contact first, therebyconnecting condenser I24 to conductor 4I0 leading to handset 400 b Wayof armature I41 and armature I59 and working contact. Next, dial tonerelay I45 completes .its operation and, at armature 146 extends .thepositive 3,2-volt potential on conductor II 0 to its lower Winding. Thetwo windings of dial tone relay I45are connected to oppose each other,.and dial tone relay I45, therefore, now starts to restore. As itpartially restores, the contact of armature I46 is opened therebydisabling the circuit hro the lower W nd n whe e pon lay I45 ceasesrestoring and re-operates over the original circuit through the upperwinding. The contact of armature I46 recloses to again complete thecircuit through the lower winding, and the described cycle of relay I45partially restoring and then re-operating is repeated over and overagain in rapid sequence. elay I45, thereioreoperates in themanner of abuzzer and, through itsoperation, impresses between the talkingconductors 41 0 and 4H an undulating volta ethrough condensers I23 andI24 which causes current to flow in the receiver of handset 400-. Thiscurrent flow in the receiver is of such acharacter that an audiblesignal is givento the calling person which he recognizes as anindication tostart dialing the number of the wanted telephone station.

The calling person then dials the required telephone number which inthis instance isassumed to be 3. The resulting interruptions of thepulsing springs of dial 402 is well-known manner cause pulsing relay IIOto correspondingly restore and re-operate three times. Pulsing relay II0 controls two independentpulsing circuits, one of which concerns-theoperation of thelocal station selector I00, and the other controlspulsing relays 220 (Figure 2) and'32 0.(Fi T.3). A description of theoperation of the local station se- 9 lector I will be given in theimmediately following paragraphs, after which the functioning of pulsingrelays 220 and 320 will be explained.

Each time pulsing relay IIO restores responsive to the dialing of thedigit 3, at armature II I it opens the circuit to relay I35 andcompletes a multiple circuit to the lower winding of relay I40 and tothe winding of motor magnet I00. Relay I35 is of the slow-to-releasetype and, therefore, remains operated during the pulse restoring periodsof relay I I0. The mentioned multiple circuit is traced from positive32-volt potential at armature spring I33 of the selector off-normalswitch and armature I31 in multiple for the first restoration of relayH0 and from armature I31 .alone for the second and third restorations ofrelay IIO, armature III and resting contact, armature I2I and restingcontact, armature I3I and resting contact, armature I39, and armatureI02 to the lower winding of relay I00 and to the winding of magnet I04.

Relay I40 operated previously through its upper winding and, being ofthe sloW-to-release type, remains operated during the pulsing period ofrelay I I0, the sustaining circuit for relay I40 between the pulsesbeing through its lower winding.

Magnet I04 operates with each pulse restoration of relay IIO to positionits pawl in well-known manner preparatory to stepping wipers IOI, 02

and I03 of station selector I00, and restores With each reoperation ofrelay H0 thereby to cause the wipers of selector I00 to be successivelystepped from contacts #26 of their respective banks to contacts #3, alsoin well-known manner.

With the first stepping of the wipers of station selector I00, armaturespring I33 of the selector off-normal switch operates to disconnectpositive 32-volt potential from the circuit leading to the winding ofrelay I35, but relay I35 is sustained between the pulses and after thepulsing by the circuit through its armature I31.

As wiper IOI leaves its bank contact #20, the circuits through the upperwindings of relay I40 and dial tone relay I05 are opened, causing relayI05 to restore fully and thereby eliminate the dial tone. As previouslyindicated, relay I00 is sustained by the circuit through its lowerwinding until the final (third) pulsing of relay IIO is completed,whereupon shortly thereafter relay M0 restores and disables theoperating circuit of magnet I00 to prevent further possible accidentalstepping of the station selector I00 wipers. Wipers I01 and I08 ofnumber-changing switch I06 are resting on the respective contacts #I(since the telephone number of the station shown in Figure 1 is thedigit "1) and, therefore, no signalling circuit is established bystation selector I 00 operating its wipers to the contacts #3 of therelated bank levels. Handset 000 is connected to the talk conductors ofthe multiple train line by way of conductor 0!!! to the negative talkconductor I32 of the train line, and by way of conductor M I, armatureI49, armature MI and resting contact to the positive talk conductor IGIof the train line, and the calling person now Waits for the answer fromthe telephone station of the car represented by Figure 3.

Returning to the pulsing operation of relay I I0 responsive to thedialing of the digit 3 by the calling person, the resulting operationsof the pulsing relays 220 (Figure 2) and 320 (Figure 3) and relatedtelephone station selectors (not shown but equivalent of selector E00 ofFigure 1) will now be explained. The restorings and reoperations ofarmature 4 i2 responsive to the dial- 10' ing of the digit 3correspondingly open and close the multiple pulsing circuits of relays220 and 320 over the 32-vol-t pulsing conductor I05 and common conductorI05 of the train line three times. Pulsing relays 230 and 320accordingly cause the related station selectors (not shown but theequivalent of selector I00) to connect with the contacts #3 of theirrespective banks, in a manner similar to that previously described forthe operation of selector I00. The station selector controlled bypulsing relay 220 is operated from the G l-volt power supply of Figure2, and the station selector controlled by pulsing relay 320 from thelOO-volt power supply of Figure 3.

No signaling circuit is completed by the. operation of the stationselector controlled by pulsing relay 220 because the telephone number ofthe station represented by Figure 2 would be some other digit than thedigit 3 (assumed to be the telephone number of the station representedby Figure 3) as, for example, the digit 2. The wipers of thenumber-changing switch of Figure 2 (not shown but the equivalent ofwipers I01 and M8) are, therefore, resting on the respective contacts#2, and the Wipers of the station selector controlled by relay 220 (notshown but the equivalentof wipers I02 and I03) are, con sequently,connected to open contacts (contacts #3 of the related number-changingswitch). The station selector controlled by pulsing relay 320, however,does complete the signalling circuit of the telephone stationrepresented by Figure 3, in a manner similar to that described in alater section of this specification concerning the circuit details of anincoming call to the telephone station represented by Figure 1, to whichdescription reference should be made for an understanding of theoperation of the signalling circuit.

Assuming now that the telephone station of Figure 3 has been signalledand a person at that station has answered the call, then the telephoneof Figure 3 station is connected to the positive and negative talkconductors I6I and I62 of the train line by way of conductors 30 I302,and the calling and called persons converse over the train line. Shoulda person at the telephone station represented by Figure 2 attempt toconnect with,

the train line while the train line is occupied with the call justdescribed, the line relay of Figure 2 (not shown but equivalent of relayI50 of Figure 1) cannot operate and, consequently, the talking circuitof the telephone handset is open at an armature equivalent to armature14s..

versation between the telephone stations of Fig ures 1 and 3, theconnection is released when thecalling person at the telephone stationof Figure 1 returns the handset 400 to the cradle. Returning the handset000 to the cradle causes cradle switch iElI to assume the contactposition opposite to that shown in Figure 4, and, as a consequence, thecircuit to relay I I0 is opened at armature spring 004% and the circuitto relay I50 at armature spring 405, and both relays restore. Atarmature I l i, relay H0 opens the circuit to relay I 35, causing relayI35 to restore after a short interval. At armature H2, relay IIO opensthe multiple holding circuit to relays 220 (Figto restore.

At armature I35, relay I35 completes a selfinterrupted circuit to magnetI04 by way of armature spring I33 of the station selector offnormalswitch, and magnet I04 self-drives wipers IOI, I02 and I03 in well knownmanner to the respective contacts #26 of the related bank levels,whereupon the off-normal switch of station selector I restores to normaland, at armature spring I33, opens the self-interrupted circuit tomagnet I04. Wipers IOI, I02 and I03 are, therefore, arrested on therespective bank contacts #26. At armature I51, relay I50 opens itsholding circuit: at armature I49, disconnects handset 400 from the trainline talk circuit; at armatures I54, I55 and I 5I respectively,reconnects the windings of pulsing relays IIO, I and I to the 32-volt,fi l-volt and l10-volt pulsing conductors of the train line; and, atarmature I52, disconnects negative 32 -volt potential from the commontrain line conductor I55. The apparatus and circuits of the controlswitch equipment of Figure 1 are now at normal.

The restorations of pulsing relays 220 (Figure 2) and 320, Figure 3)cause the release of the associated control equipments of Figures 2 and3 in a manner similar to that just described for the release of thecontrol equipment of Figure l.

The control equipments of Figures 2 and 3 and the entire train line arenow in the normal unoperated positions, and the train telephone systemis available for another call.

Considering now the case where the train line is in prior use (busy)when a person at the telephone station of Figure 4 attempts to initiatea call, then relay I is already in the operated position as a result ofthe prior call. The circuit to line relay I is, therefore, open atarmature I34 and, consequently, the attempted (second) call isineffective. The absence of dial tone in handset 400 is an indication tothe calling person that the train telephone system is already in use andthat this call must be delayed until the train line becomes available.As soon as the prior connection is released, relay I35 restores in themanner previously described, thereby extending conductor 408 to thewinding of relay I50, and a call can now be successfully originated atthe telephone shown in Figure 4. Line relay I50 is of theslow-to-operate type in order that its operation is momentarily delayedto permit ample time for previously operated station selectors (I00 inFigure 1) to home to the respective bank contacts #26.

Outgoing call from wear equipped with a 64-volt power supply Should thecalling station be located in a car equipped with a 64-volt power supplyand the called station located in a car equipped with a 32-volt powersupply, then the circuit operation is essentially the same as thatdescribed in the preceding section of this specification. The pulsingrelays involved in this instance, however, are relay 2I0 of Figure 2,relay 330 of Figure 3, and relay I 20 of Figure 1.

Relay 2I0 responds to the dial interruption over conductor 20! and, inaddition to causing the stepping of the station selector of Figure 2(not shown but the equivalent of selector I00) pulses relay I20 ofFigure '1 and relay 330 of Figure 3 over the v64-volt pulsing circuit ofthe train line. In turn, relay I20 causes the stepping of stationselector I00 over its 32-.volt power supply to the bank .contacts #I,thereby completing the signalling circuit of Figures 1 and 4. Relay 330causes the stepping of the related station selector (not shown but theequivalent of selector I00) over its ll0-volt power supply to the bankcontacts #I, but does not complete the signalling circuit of Figure 3(signalling circuit not shown but the equivalent of that shown in Figurel), which is accessed through bank contacts #3.

Outgoing call from a car equippedwith a 1,1 O-uolt power supply Shouldthe calling station be located in a car equipped with a '1'l0-vo1t powersupply and the called station located in a car equipped with a G l-voltpower supply, then the circuit operation is essentially the same asthatdescribed in the section titled Outgoing Call From a Car EquippedWith a .32-Volt Power Supply. The pulsing relays involved in thisinstance, however, are relay 3I0 of Figure 3, relay 230 of Fig ure 2,and relay I30 of Figure l.

Relay'3l0 responds to the dial interruptions over conductor 30! and, inaddition to causing the stepping of the station selector of Figure 3(not shown but the equivalent of selector I00), pulses relay 230 ofFigure 2 and relay I30 of Figure 1 over the -v0lt pulsing circuit of thetrain line. In turn, relay 230 causes the stepping of the relatedstation selector (not shown but the equivalent of selector I00) over its64-volt power supply to the bank contacts #2, thereby completing thesignalling circuit of the telephone station represented by Figure 2(signalling circuit not shown but the equivalent of that shown in Figure1). Relay I30 causes the stepping of selector I00 over its .32-voltpower supply to the bank contacts #2, but does not complete thesignalling circuit of Figure l which is accessed through bank contacts#I.

Power supplies to pulsing relays and related station selectors From theexplanations given in the preceding three sections concerning thecircuit operations of outgoing calls initiated in cars equipped withpower supplies of 32 volts, 64-vo1ts and 110 volts, respectively, itwill be noted that the three pulsing relays in each instance areoperated from the power supply of the car in which the calling stationis located, the pulsing relay of the calling station being operated overa local circuit controlled by the dial of the calling station and theother two pulsing relays over a pulsing aircuit or the multiple trainline controlled by the pulsing relay of the calling station. It will bealso noted that the station selectors controlled respectively by thethree pulsing relays are each operated over a local circuit from thepower supply of the car in which that particular station selector islocated and, consequently, there is no interconnection of the powersupplies of two or more cars. It will, therefore, be appreciated thatthe present invention provides new and novel means for isolating thediiierent voltage power supplies of two or more cars, and that a vastlyimproved, efficient, and flexible train telephone system, free from thepossibilities of undesirable power supply interferences or possibledamage resulting therefrom, has been accomplished.

Restricted service The train telephone system is so arranged 75, thatcalls initiated at certain stations, such as stations located insleeping cars, can only be extended to certain other stations, such asstations located in club and dining cars, whereas calls initiated atstations located in the club and dining cars, for example, can beextended to any other station in the system. Restriction of outgoingcalls is accomplished at any station in a novel manner by installing alocking type lever or push key switch, (such as I in Figure 1), in thecontrol equipment of such telephone station to be restricted, andplacing the key switch in the operated (closed) position to make therestriction efiective.

Referring now to Figure l, the contacts #9 and #IQ of the bank levelassociated with wiper IIlI of station selector I00 are multipliedtogether and connected to armature I55 of line relay I50: the contact ofarmature I55 is connected to the armature spring of restriction keyswitch I09; and the contact of restriction key switch I 39 is connectedto conductor car. With restriction key switch I89 in the operated(closed) position, it will be observed that when the dial 402 of thecalling station represented by Figure 1 is operated, the circuit throughkey switch I09 is completed only when the single digit 9 or the firstdigit 0 of a two or three digit numbar is dialed. The circuit throughkey switch I09 is traced from positive 32-volt potential on wiper IOI,bank contact #0, armature I56 (relay IEia operated responsive to theinitiation of the call), key switch I30 to conductor dill. The pulsingcontacts of dial 352 are shunted when positive potential is extended toconductor 00? through switch key I59, and pulsing relay IIEi is,therefore, held continuously operated. As a consequence, the wipers ofstation selector I00 cannot be pulsed beyond the respective contacts #5.

Under the conditions outlined in the preceding paragraph, it is apparentthat only the telephone stations having the single digit call numbers 2,3, 4, 5, 6, '7, 8 and 9 are accessible to the station of Figure 1.Should the calling person at the station of Figure 1 dial a two-digit ora three-digit call number, the wipers of station selector Iilil will bestepped to the respective bank contacts #9 and held on the contactsbecause the pulsing contacts of dial ltii are shunted by the positivepotential through key switch 533 in the manner just described when wiperilll reaches its contact #3. Such an attempted two-digit or three-digitcall is, therefore, ineffective. The station of Figure 1, however, isaccessible to the stations restricted to the station of Figure 1 sincethe call number of the station of Figure l is the single digit 1.

In addition to the mentioned eight single-digit stations accessible tothe station of Figure 1 when switch 503 is in the closed position, thetwo-digit stations having the call numbers 01 through 09 can also bemade available to the station of Figure 1. This is accomplished byconnecting only contact #53 of the bank level associated with wiper Ifilor" station selector I00 to armature I55 of line relay i5 3, bankcontact #5 in this instance not being multipled with bank contact Thecircuit through key switch I33 is now completed only when the last digit9 of the two-digit call number "09 or the second digit 0 of athree-digit call number is dialed at dial 532, and pulsing relay H0 isheld continuously operated with wiper ItI resting on break contact #IQ.Under these conditions only the three-digit stations having the 14 callnumbers 001, 002, 003 and 004 are not accessible to the station ofFigure 1.

Incoming call to a. car equipped with a 32-volt power supply I Assumingnow that a person in a car equipped, for instance, with a (i l-voltpower supply initiates a call for the telephone station associated withFigure 1 (32-volt power supply), then the circuit operation is asfollows:

The calling person in the car represented by Figure 2 initiates the calland, after receiving dial tone, dials the digit 1 (telephone number ofthe station represented by Figure 1), in a similar manner to thatdescribed in the section of this specification titled Outgoing Call Froma Car Equipped With a 32-Volt Power Supply. In this instance, however,the calling station is associated with a car having a 64- volt powersupply and, therefore, pulsing relay 2I0 in Figure 2, pulsing relay I20in Figure 1, and pulsing relay 330 in Figure 3 respond to the dialing ofthe digit 1. The pulsing potential for relay I20 is traced from positivefi l-volt potential on train line conductor I 64 by way of the pulsingarmature 2I2 through the resistor I22 and the winding of relay I20 tonegative 64-volt potential on the train line common conductor I55. RelayI2il operates over this pulsing circuit.

At armature I2I and working contact, relay I20 completes a circuit torelay I from positive 32-volt potential by way of station selector offnormal armature spring I33 and resting contact, armature III and restingcontact, to the winding of relay I35 and negative 32-volt potential,causing relay I35 to operate. At armature I31, relay I35 completes amultiple circuit to its winding independent of off-normal armaturespring I33: at armature I34, opens a point in the circuit to line relayI50 thereby to prevent relay I50 from operating when the called stationanswers; and, at'armature I33, completes a circuit to relay M0 frompositive 32- volt potential on wiper I0! of selector I00, 26th contactof bank associated with wiper IOI, armature I38, upper winding of relayI40 to negative 32-volt potential, causing relay I 40 to operate.

When pulsing relay I20 restores responsive to the dialing of the digit1, at armature IZI it opens the circuit to relay I35 and completes amultiple circuit to the lower winding of relay M0 and to the winding ofmotor magnet I04. Relay I35 is of the slow-to-release type and,

therefore, does not restore during the pulsing.

The mentioned multiple circuit is traced from positive 32-volt potentialat armature spring I33 of the selector off-normal switch and armature I3! in multiple, armature III and resting contact, armature I2I andresting contact, armature I3I and resting contact, armature I30, andarmature I42 to the lower winding of relay I40 and to the winding ofmagnet I04.

Relay I40 operated previously through its upper winding and, being ofthe slow-to-release r' type, remains operated during the pulsing periodof relay I20. Magnet I04 operates with the pulse restoration of relayI20 to position its pawl in well-known manner preparatory to steppingwipers IOI, I02 and I03 of station selector I00, and restores after thepulsing to cause the wipers of selector I00 to be stepped from contacts#26 of the respective banks to contacts #I, also in well-known manner.It should be noted at this time that pulsing relay I20 is operated fromthe G l-volt power supply of Figure 2 on the train line and stationselector I00 from the local 32-volt power supply of Figure 1 under thecontrol of pulsing relay I20.

With the stepping of the wipers of station selector I00, armature springI33 of the selector oil-normal switch operates to disconnect positive32-volt potential from the circuit leading to the winding of relay I35,but relay I does not restore during the pulsing and is sustained afterthe pulsing by the circuit through its armature I31. As wiper IOI leavesits contacts #20, the circuit through the upper winding of relay I isopened, whereupon shortly thereafter relay I40 restores and disables theoperating circuit of magnet I04. Wipers I01 and I00 of number-changingswitch I06 are resting on the respective contacts #I (since thetelephone number of the station shown in Figure 1 is the digit 1), and acircuit is, therefore, completed from positive 32-volt potential atterminal II'I, conductor 400, lower contact associated with armaturespring 405 of cradle switch 00I, interrupter armature of buzzer 403,windings of buzzer 303, conductor 000, armature I59 and resting contact,armature I41 and resting contact, armature I43, wiper I01, contact #I ofbank level associated with wiper I0'I, contact #I of bank levelassociated with Wiper I02, wiper I02, resistor H5 to negative32-voltpotential, causing buzzer 403 to operate as a calling signal.

Responsive to a person at the called station lifting handset 600 fromthe cradle, cradle switch MI is caused to assume the contact positionshown in Figure 4. The circuit for buzzer 403 is now open at armaturespring 405, and handset 400 is connected to the talk conductors of thetrain line by way of conductor M0 to the negative talk conductor I62 ofthe train line, and by way of conductor 4H, wiper I03, contact #I of thebank level associated with wiper I03, contact #I of the bank levelassociated with Wiper I08, wiper I08, armature MI and resting contact tothe positive talk conductor IBI of the train line. The calling andcalled persons then converse over the train line, and upon thetermination of the conversation, the connection is released in a similarmanner to that described in the section titled Outgoing Call From a CarEquipped With a 32-Volt Power Supply.

Considering now the case where an incoming call to the telephone stationassociated with Figure 1 (32-volt power supply) is initiated at thetelephone station of a car equipped with 110- volt power supply, thenthe pulsing relays involved are relay 3I0 of Figure 3, relay 230 ofFigure 2 and relay I30 of Figure 1. In this instance, relay 3I0 respondsto the dial interruption over conductor 30'! and, in addition to causingthe stepping of the station selector of Figure 3 (not shown butequivalent of selector I00), pulses relay 230 of Figure 2 and relay I30of, Figure 1 over the 1l0-v0lt pulsing circuit of the train line. Inturn, relay 230 causes the stepping of its related station selector (notshown) over its 64-volt power supply, and relay I30 causes the steppingof station selector I00 over its 32- volt power supply. In otherrespects, the details of this call are essentially the same as thosejust described for the case where the calling station is located in acar represented by Figure 2.

It should be understood that the calling telephone station can equallyas well be located in a car equipped with a 32-volt power supply, inwhich case the operation of the control equipment of the calling stationwould be similar to that explained in the section titled Outgoing CallFrom a Car Equipped With a 32-Volt Power Supply. The pulsing relaysinvolved would then be relay III) of the calling station, relay H0 ofthe called station, relay 220 of Figure 2, and relay 320 of Figure 3.

Dialing telephone station call numbers Should the call number of adesired telephone station be less than 10, the station selectors in allcars of the train telephone system will be stepped to the equivalentcontacts of the respective banks, upon the dialing of the call number.

Should the call number of a desired telephone station comprise twodigits (see Figure 7), the first dialed digit 0 causes the stationselectors to be stepped to the respective bank contacts I 0 (which arenot wired to contacts of the related telephone number-changing switchessuch as I06), and the second dialed digit then causes the stationselectors to be stepped to the proper contacts of the group #II to andincluding #I0, whereupon the signalling circuit of the called station iscompleted in a similar manner to that explained in the section titledIncoming Call to a Car Equipped With a 32-Volt Power Supply.

Should the call number of a desired telephone station comprise threedigits, the first dialed digit (0) causes the station selectors to bestepped to the respective contacts #II) (which are not wired to contactsof the related telephone number-changing switches), the second dialeddigit (also 0) causes the station selectors to be stepped to thecontacts #20 (which are not wired to contacts of the related telephonenumberchanging switches), and the third (last) dialed digit causes thestation selectors to be stepped to the proper contacts of the group #ZIto and including #24, whereupon the signalling circuit of the calledstation is completed.

Contacts #I0 and #20 of the banks associated with the wipers such as IOIare wired to the contacts of armatures such as I38 in order that therelays such as I40 are sustained through their respective upper windingsas long as the station selector wipers are resting on either contacts#I0 or contacts #20.

Should a calling person dial a number which would ordinarily step thewipers of the station selectors beyond contacts #24 of th respectivebanks and onto contacts of the first (singledigit) group of bankcontacts, then as the wiper at the calling station equivalent of wiperIOI connects with its contact #25 positive potential is extended to theconductor equivalent of conductor 00? thereby to shunt the pulsingcontacts of the calling dial. The pulsing relay equivalent to relay I I0is, therefore, held in the operated position and no further movement ofthe station selectors is possible at this time. s CIII-IaVCiingdescribed the invention, what is con- 1 ere new and is desired to have rLetters Patent is set forth in the follosvi gzl i m 1. In a telephonesystem, the combination of a plurality of stations, each said stationhav m a p ty of relays equal in number to the nun": ber of saidstations, a line interconnecting said stations, said line havingconductors equal in number to said number of relays in any one of saidstations, means in each of said stations connect ng each of said relaysin each of said statrons to a different one of said conductors of said lne, and means controlled by any one of said statrons for operating oneof said relays in each of 17 said other stations in unison over thecorresponding connected conductor of said line.

2'. In a telephone system as claimed in claim 1 wherein said last meansincludes a power source located at the controlling station for supplyingpower to operate said last one relay in each of said other stations.

3. In a telephone system, a plurality of stations each having aplurality of relays equal in number to the number of said stations, apower source at each of said stations, a line interconnecting saidstations, said line having conductors equal in number to the number ofsaid relays at one of said stations, means at each of said stations forconnecting each of said relays at each of said stations to differentones of said conductors of said. line, and means controlled by one ofsaid stations for operating one of said relays in each of said otherstations over the corresponding connected conductor of said line and foroperating one of said relays at said one controlling station, said powersource at said one controlling station included in said last means.

4. In a telephone system, three stations each having an individual powersource, a line interconnecting said stations in a given order ofrelative positions, means at one of said station for connecting itsindividual power source to said line, means at a second of said stationsfor connecting its individual power source to said line, means at thethird one of said stations for connecting its individual power source tosaid line, a plurality of relays at each of said stations, means foroperating certain of said relays from one of said power sources oversaid line, means for operating other of said relays from another of saidpower sources over said line, means for interconnecting said stations ina different order of positions, said operation of said certain relaysand said operation of said other relays effective irrespective of theparticular positional interconnection of said stations.

5. In a telephone system, a plurality of stations each including animpulsing device, a line interconnecting said stations, automaticswitches individually associated with said stations, each of saidswitches having a predetermined operating position and a plurality ofother operating positions individually corresponding to said stations,means responsive to the initiation of a call at a calling one of saidstations for conditioning all said switches to respond to impulsestransmitted from said calling station, means responsive to impulsestransmitted from said impulsing device at said calling station forcausing all said switches to operate to the respective one positionscorresponding to a called one of said stations or to said respectivepredetermined positions depending upon the number of impulsestransmitted from said impulsing device at said calling station, meansresponsive to the operation of the switch at said calling station to itssaid predetermined position for rendering all said switchesnon-responsive to further transmitted impulses whereby calls from saidcalling station to certain of said other stations are prevented, and amanually operative device at said calling station for rendering saidlast mentioned means ineffective thereby to permit calls from saidcalling station to said certain other stations.

6. In a telephone system, two stations, a trunk line interconnectingsaid stations, an impulseresponsive switch, an impulsing device and arelay at one of said stations, an impulse-responsive switch at saidother station, said 18 switches each having a predetermined operatingposition and a plurality of other operating positions beyond saidpredetermined position, means responsive to the initiation of a call atsaid one station for operating'said relay, means responsive to theoperation of said impulsing device at said one station for pulsing saidoperated relay, means responsive to said pulsing of said relay forcorrespondingly pulsing said switch at said one station, meansresponsive to said pulsing of said relay for correspondingly pulsingsaid switch at said other station overrsaid trunk line, means responsiveto said switch at said one station advancing to its saidrpredeterminedposition for rendering said impulsing device at said one stationthereupon ineffective to prevent further advancing of both said switcheswhen the dialed digit has a value corresponding to one of said otherpositions which are beyond said predetermined position, and means: atsaid one station controllable at will for rendering said last mentionedmeans ineffective, thereby to permit both said switches to advancebeyond said predetermined positions when. the dialed digit has a valuecorresponding to one of said other positions.

'7. In a signalling system, the combination with a station. having asignal, of a switch having a rotatable connecting brush and a plurality.of terminals accessible -to, said brush, a selector having a wiper andaplurality of bank contacts accessible to saidwiper, said terminals ofsaid switch and said bank contacts of said selector. beinginterconnected, means connecting said signal to said brush of saidswitch, manually controlled means for quickly and conveniently .rotatingsaid brush of said switch. into contact with any desired terminal ofsaid switch to thereby connect said signal to any one of the bankcontacts of said selector corresponding to the terminal of said switchupon which said brush of said switch is now resting, said connection ofsaid signal being accomplished solely by' said manually actuatedmovement of said brush of said switch without unsoldering wires orchanging jumpers, means responsive to received impulses for pulsing saidselector to cause said wiper of said selector to select said one bankcontact of said selector corresponding to said one terminal of saidswitch, and means responsive to said selection of said one bank contactof said selector for completing an operating circuit to said signal,whereby said signal may be operated in response to any desired number ofreceived impulses dependent on the position of said brush.

8. In a telephone system, two stations, one of said stations having aselector, signalling means, a first relay and a second relay, said otherstation having a selector and signalling means, a line having aplurality of conductors interconnecting said stations, said second relaybeing connected to one of said conductors of said line and controllablethereover by said other station, means responsive to the initiation of acall at said one station for disconnecting said second relay from saidone conductor of said line to prevent said other station from operatingsaid second relay, means responsive to said initiation of said call foroperating said first relay, means controlled by said one station foralternately restoring and re-operating said first relay, meansresponsive to said restorations and re-operations of said first relayfor correspondingly stepping said selector of said one station toprevent the operatiori of sardi signalling: means oi said: one stat-1am:mean lu' img: anoth'ei iconductor' of saidiline resno'nsi sai'dr'estorations" and re operationsfof said: first relay forcorrespondingly stepping, said? selector ofa said other station to:cause: theiioperationa of: saidv signalling: means of saidother station;means responsive: to? the initiation: of: a call at: said stationat: atime said oneistationris idleitfor operatin'g said-second relayoveiisaidcone conductor of said line; means thereaftercontrolled by: said:other station for alternately restoring and're 'operating saidsecondfielay; and means: responsive to' saidirestoratio'nsf and:re-01Jeration$r of. said second relayifor correspondingly stepping'saidselector ofsaid' one 'station to cause the operation ofsaidsignallingmea' saiditone sta'tion',v

9's" 1 In aetelephone system, two stations; one of said stationshavingaatselector:signalling means; aii' impulsingdeticesa firstzrelay;a second relay; and ar thi'rd relay, said 'other station I having a;selector, signalling mean'siand a'n imp'nlsing. de asline havingi'a p'lura'lity of condu'ctOrsminF teioonnectingcsaid stations;:-said thirdrelay being connectedto one of saidlconductors or saidline andcontrollable thereover by; said' otherstation, means responsive to a:call at said: one station for: operating said first relay to" disconnectsaid: third relay froni said'onebondimtor of said line thereby: toprevent said-other station from operatingssaidthird relay; means'responsivefto' said operation Qf 'sai'd' first relay? for operating:said sedond'rel'ay, meansrresponsive to' the operation of saidimpulsingu device at said one station for alternately restoring-"5andJre-operating said sec- 0nd relayracoordingfto the value of'thedialed digit means responsiive'ito said restorations and 20're-operationsrof said second relay for correspond.- ingly stepping.'saidselector ofssaid one station to .:prevent therop'eration ofsaidsignalling means of" said one station, means including anotherconductor of saidlline responsive to said restoration'sand.re=operations of said 'second relay for correspondingly stepping saidselector of said other station-to cause the operation of saidsignailing" means of 4 said other station, means responsiverto theinitiation of a, call at said other station; at. a't'imersaid: firstrelay is in its normal unoperate'd positiontfor"operating-o said thirdrelay: over saidone conductor of: saidfiline, means thereafterresponsive to theoperat'ionof: said impulsing :device at: said. other:stationiforf a1- te-rnately restoring andreeoper'ating said third relayaccording to the valu of theidialedx'digit; and. means responsive. to:said restorations and re -operationsof saidxthirdsrelay: for correspondI ingly:steppinglsaid':selector of said: one-station;

to cause said-signalling meansiof' said: one: station to operate.

.STEPHAN J BARTHA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,200,811 Clement Oct. 10, 19161,727,133 Richardson Sept. 3, 1929 1,841,733 Hershey Jan. 19,. 19321,969,075 Henry Aug. '7, 1934 1,992,389 Moser Feb. 26, 1935 2,183,839Ja'uch Dec. 19,1939

